The present invention relates to digital switching systems in the field of electronic communications and more particularly to improvements in construction of a speech path switch of a high-speed packet switching system which performs switching operation by using a fixed length packet.
In order to handle communications requiring high speed and wide band, the high-speed packet switching technique using a packet of a fixed length has been studied. One of features of the packet switching resides in that each packet has a header and a destination of each packet can be known from the header. In other words, the packet switching permits self-routing. Accordingly, high-speed switching operation can be ensured by reading the contents of the header through the use of hardware and carrying out switching in accordance with routing information described in the header. A typical example of this type of switch is disclosed in JP-A-59-135994 entitled "TDM Switching System".
On the other hand, for the purpose of constructing a large-scale speech path switch, it is general practice that switch elements each having a certain size are connected in multi-stage to expand the size. An example of this type of switch is disclosed in, for example, FIG. 5 of JP-A-59-501034 (corresponding to W0 84/00265) entitled "High-speed Packet Switching".